ViaVersion/common/src/main/java/com/viaversion/viaversion/protocols/protocol1_20_2to1_20/Protocol1_20_2To1_20.java

/*
 * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
 * Copyright (C) 2023 ViaVersion and contributors
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package com.viaversion.viaversion.protocols.protocol1_20_2to1_20;

import com.viaversion.viaversion.api.Via;
import com.viaversion.viaversion.api.connection.UserConnection;
import com.viaversion.viaversion.api.minecraft.entities.Entity1_19_4Types;
import com.viaversion.viaversion.api.protocol.AbstractProtocol;
import com.viaversion.viaversion.api.protocol.packet.Direction;
import com.viaversion.viaversion.api.protocol.packet.PacketWrapper;
import com.viaversion.viaversion.api.protocol.packet.State;
import com.viaversion.viaversion.api.rewriter.EntityRewriter;
import com.viaversion.viaversion.api.rewriter.ItemRewriter;
import com.viaversion.viaversion.api.type.Type;
import com.viaversion.viaversion.data.entity.EntityTrackerBase;
import com.viaversion.viaversion.protocols.base.ServerboundLoginPackets;
import com.viaversion.viaversion.protocols.protocol1_19_4to1_19_3.ClientboundPackets1_19_4;
import com.viaversion.viaversion.protocols.protocol1_19_4to1_19_3.ServerboundPackets1_19_4;
import com.viaversion.viaversion.protocols.protocol1_20_2to1_20.rewriter.BlockItemPacketRewriter1_20_2;
import com.viaversion.viaversion.protocols.protocol1_20_2to1_20.rewriter.EntityPacketRewriter1_20_2;
import com.viaversion.viaversion.protocols.protocol1_20_2to1_20.packet.ClientboundConfigurationPackets1_20_2;
import com.viaversion.viaversion.protocols.protocol1_20_2to1_20.packet.ClientboundPackets1_20_2;
import com.viaversion.viaversion.protocols.protocol1_20_2to1_20.packet.ServerboundConfigurationPackets1_20_2;
import com.viaversion.viaversion.protocols.protocol1_20_2to1_20.packet.ServerboundPackets1_20_2;
import com.viaversion.viaversion.protocols.protocol1_20_2to1_20.storage.FakeProtocolState;
import com.viaversion.viaversion.rewriter.SoundRewriter;
import com.viaversion.viaversion.rewriter.StatisticsRewriter;
import com.viaversion.viaversion.rewriter.TagRewriter;
import org.checkerframework.checker.nullness.qual.Nullable;

import java.util.UUID;

public final class Protocol1_20_2To1_20 extends AbstractProtocol<ClientboundPackets1_19_4, ClientboundPackets1_20_2, ServerboundPackets1_19_4, ServerboundPackets1_20_2> {

    private final EntityPacketRewriter1_20_2 entityPacketRewriter = new EntityPacketRewriter1_20_2(this);
    private final BlockItemPacketRewriter1_20_2 itemPacketRewriter = new BlockItemPacketRewriter1_20_2(this);

    public Protocol1_20_2To1_20() {
        // Passing the class types into the super constructor is needed for automatic packet type id remapping, but can otherwise be omitted
        super(ClientboundPackets1_19_4.class, ClientboundPackets1_20_2.class, ServerboundPackets1_19_4.class, ServerboundPackets1_20_2.class);
    }

    @Override
    protected void registerPackets() {
        // TODO Updated NBT type used in: block entity, chunk, tag query, entity metadata data, item type, mob effect

        // TODO Handle Enabled features and tags before configuration phase end
        // TODO Make sure Paper/Velocity handle a 0,0 uuid fine during login

        // Lesser:
        // TODO Player info, replace profile with missing name with null?
        // TODO Scoreboard objective probably okay, but there are refactors to the id
        super.registerPackets();

        final TagRewriter<ClientboundPackets1_19_4> tagRewriter = new TagRewriter<>(this);
        tagRewriter.registerGeneric(ClientboundPackets1_19_4.TAGS);

        final SoundRewriter<ClientboundPackets1_19_4> soundRewriter = new SoundRewriter<>(this);
        soundRewriter.register1_19_3Sound(ClientboundPackets1_19_4.SOUND);
        soundRewriter.registerSound(ClientboundPackets1_19_4.ENTITY_SOUND);

        new StatisticsRewriter<>(this).register(ClientboundPackets1_19_4.STATISTICS);

        registerClientbound(ClientboundPackets1_19_4.SCOREBOARD_OBJECTIVE, wrapper -> {
            final byte slot = wrapper.read(Type.BYTE);
            wrapper.write(Type.VAR_INT, (int) slot);
        });

        registerServerbound(State.LOGIN, ServerboundLoginPackets.HELLO.getId(), ServerboundLoginPackets.HELLO.getId(), wrapper -> {
            wrapper.passthrough(Type.STRING); // Name

            final UUID uuid = wrapper.read(Type.UUID);
            wrapper.write(Type.OPTIONAL_UUID, uuid);
        });

        // Deal with the new CONFIGURATION protocol state the client expects
        registerServerbound(State.LOGIN, ServerboundLoginPackets.LOGIN_ACKNOWLEDGED.getId(), -1, wrapper -> {
            wrapper.user().get(FakeProtocolState.class).setConfigurationState(true);
            wrapper.cancel();
        });

        registerServerbound(State.CONFIGURATION, ServerboundConfigurationPackets1_20_2.FINISH_CONFIGURATION.getId(), -1, wrapper -> {
            wrapper.user().get(FakeProtocolState.class).setConfigurationState(false);
            wrapper.cancel();
        });
        registerServerbound(State.CONFIGURATION, ServerboundConfigurationPackets1_20_2.CUSTOM_PAYLOAD.getId(), ServerboundPackets1_19_4.PLUGIN_MESSAGE.getId(), wrapper -> {
        });
        registerServerbound(State.CONFIGURATION, ServerboundConfigurationPackets1_20_2.KEEP_ALIVE.getId(), ServerboundPackets1_19_4.KEEP_ALIVE.getId(), wrapper -> {
        });
        registerServerbound(State.CONFIGURATION, ServerboundConfigurationPackets1_20_2.PONG.getId(), ServerboundPackets1_19_4.PONG.getId(), wrapper -> {
        });
        registerServerbound(State.CONFIGURATION, ServerboundConfigurationPackets1_20_2.RESOURCE_PACK.getId(), ServerboundPackets1_19_4.RESOURCE_PACK_STATUS.getId(), wrapper -> {
        });

        // Sad emoji
        cancelClientbound(ClientboundPackets1_19_4.UPDATE_ENABLED_FEATURES);

        registerServerbound(ServerboundPackets1_20_2.CONFIGURATION_ACKNOWLEDGED, null, wrapper -> {
            wrapper.user().get(FakeProtocolState.class).setConfigurationState(false);
            wrapper.cancel();
        });

        // TODO Check if we can just not send batches (probably fine like this)
        cancelServerbound(ServerboundPackets1_20_2.CHUNK_BATCH_RECEIVED);
    }

    @Override
    public void transform(Direction direction, State state, PacketWrapper packetWrapper) throws Exception {
        final boolean configurationState = packetWrapper.user().get(FakeProtocolState.class).isConfigurationState();
        if (direction == Direction.SERVERBOUND) {
            // Redirect packets during the fake configuration phase
            // This might mess up people using Via API/other protocols down the line, but such is life. We can't have different states for server and client
            final State newState = configurationState ? State.CONFIGURATION : state;
            super.transform(direction, newState, packetWrapper);
            return;
        }

        // Make sure we don't send the client any packets from another protocol state
        if (configurationState) {
            // TODO Queue these packets to send them later
            Via.getPlatform().getLogger().warning("Cancelled packet " + packetWrapper.getId() + " sent during configuration state");
            packetWrapper.cancel();
            super.transform(direction, state, packetWrapper);
            return;
        }

        // Map some of them to their configuration state counterparts
        final int unmappedId = packetWrapper.getId();
        if (state == State.PLAY && unmappedId != ClientboundPackets1_19_4.JOIN_GAME.getId()) {
            if (unmappedId == ClientboundPackets1_19_4.PLUGIN_MESSAGE.getId()) {
                packetWrapper.setPacketType(ClientboundConfigurationPackets1_20_2.CUSTOM_PAYLOAD);
            } else if (unmappedId == ClientboundPackets1_19_4.DISCONNECT.getId()) {
                packetWrapper.setPacketType(ClientboundConfigurationPackets1_20_2.DISCONNECT);
            } else if (unmappedId == ClientboundPackets1_19_4.KEEP_ALIVE.getId()) {
                packetWrapper.setPacketType(ClientboundConfigurationPackets1_20_2.KEEP_ALIVE);
            } else if (unmappedId == ClientboundPackets1_19_4.PING.getId()) {
                packetWrapper.setPacketType(ClientboundConfigurationPackets1_20_2.PING);
            } else if (unmappedId == ClientboundPackets1_19_4.RESOURCE_PACK.getId()) {
                packetWrapper.setPacketType(ClientboundConfigurationPackets1_20_2.RESOURCE_PACK);
            } else if (unmappedId == ClientboundPackets1_19_4.UPDATE_ENABLED_FEATURES.getId()) {
                packetWrapper.setPacketType(ClientboundConfigurationPackets1_20_2.UPDATE_ENABLED_FEATURES);
            } else if (unmappedId == ClientboundPackets1_19_4.TAGS.getId()) {
                packetWrapper.setPacketType(ClientboundConfigurationPackets1_20_2.UPDATE_TAGS);
            }
            return;
        }

        super.transform(direction, state, packetWrapper);
    }

    @Override
    protected @Nullable ServerboundPackets1_20_2 configurationAcknowledgedPacket() {
        return null; // Don't handle it in the transitioning protocol
    }

    @Override
    public void init(final UserConnection user) {
        user.put(new FakeProtocolState());
        addEntityTracker(user, new EntityTrackerBase(user, Entity1_19_4Types.PLAYER));
    }

    @Override
    public EntityRewriter<Protocol1_20_2To1_20> getEntityRewriter() {
        return entityPacketRewriter;
    }

    @Override
    public ItemRewriter<Protocol1_20_2To1_20> getItemRewriter() {
        return itemPacketRewriter;
    }
}